The active ingredient in ECO-PCO ACU is 2-penethyl-propionate. It is derived from alcohol and targets a neurotransmitter that only exists in invertebrates (a.k.a. bugs). Therefore, there is less risk to the human nervous system and it is labeled a natural product.
This spray will drop house flies (even gigantic horse flies) instantly on contact. They'll crash and burn like The Hindenburg blimp. If you hit a larger crawling bug like a spider, house centipede or jerusalem cricket, IT WILL definitely die but it can take 1 minute to 5 minutes.
The more powerful concoction of this product for crawling insects is EcoExempt KO. EcoExempt KO is FIVE PERCENT (5%) 2-penethyl-propionate, whereas ECO PCO ACU is only 0.10% 2-penethyl-propionate. The tradeoff is that EcoExempt KO is NOT a misting aerosol and so is less useful against flying insects. But EcoExempt KO will disable large crawling insects (and by LARGE I mean Jerusalem Crickets, which are the size of a small mouse) instantly -- and kill them more quickly than this product.
But make no mistake -- ECO PCO ACU absolutely kills on contact like it states. None of my hundreds of insect victims of every size ended up living . . . just understand that if your goal is instant knockout of crawling insects, another product by this manufacturer (EcoExempt KO) is a bit more "instant."

This product is effective with not only killing roaches on the spot but allows them to crawl back to their nests and infect the others. The ingredients are not as toxic as other products so I feel confident in using it. I can see the light at the end of this tunnel with this product.